Many metalworking processes involve manipulating and processing of continuous metal strips. Processing metal as strips allows for long lengths of metal to be processed quickly, but requires that the metal strip remain centered within a certain variance from the desired passline of the processing equipment. If the strip wanders too far off the desired passline of the equipment, the strip may make undesired contact with edges of the equipment, the strip may not be processed correctly (e.g., not heated or cooled evenly), or other undesirable, dangerous, or costly effects may result. In certain equipment, the metal strip is being held in high tension, and active steering may not be necessary. However, the need for active steering or control can increase when the metal strip is not being held in high tension, such as when the strip is being first fed into a cold-rolling mill or when processing the metal strip in a continuous annealing line. Active steering can be useful in other circumstances as well.
Additionally, certain metals, such as aluminum, can be harmed by contact with equipment. The use of non-contact steering equipment can be desirable, especially when processing a metal when the metal is soft (e.g., due to heating). Additionally, certain metals can be harmed by localized hotspots in the metal.